The relationship between population density and rate of dispersal and tendency to aggregate in two species of fresh-water amphipods, Hyalella azteca (Saussure) and Cammarus pseudolimnaeus Bousfield, was tested by laboratory experiment. Populations of H. azteca showed an inverse relationship between initial density and dispersal rate; this relationship is a function of the tendency of populations of higher densities to form aggregations. The dispersal rate of G. pseudolimnaeus was not appreciably affected by changes in population density, and increased density did not result in aggregation. Both species aggregated around vegetation in preference to aggregation around other amphipods. The non-aggressive behavior and pronounced thigmotaxis of both species contribute to their aggregation and dispersal behavior.
Proceedings of the Iowa Academy of Science
©1964 Iowa Academy of Science, Inc.
Clampitt, Philip T.
"Dispersal Related to Density in the Amphipods Hyalella azteca and Gammarus pseudolimnaeus,"
Proceedings of the Iowa Academy of Science, 71(1), 474-484.
Available at: https://scholarworks.uni.edu/pias/vol71/iss1/72